chore(NA): update versions after v8.8.0 bump (#150570)

This PR is a simple update of our versions file after the recent bumps

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Co-authored-by: Kibana Machine <42973632+kibanamachine@users.noreply.github.com>

versions.json

@@ -2,11 +2,17 @@
   "notice": "This file is not maintained outside of the main branch and should only be used for tooling.",
   "versions": [
     {
-      "version": "8.7.0",
+      "version": "8.8.0",
       "branch": "main",
       "currentMajor": true,
       "currentMinor": true
     },
+    {
+      "version": "8.7.0",
+      "branch": "8.7",
+      "currentMajor": true,
+      "previousMinor": true
+    },
     {
       "version": "8.6.2",
       "branch": "8.6",